Diseases of the urinary tract present a growing healthcare problem worldwide. One of the most common diseases of the urinary tract is interstitial cystitis. Interstitial cystitis (IC) is a clinical syndrome of frequency, urgency, and/or pelvic pain in the absence of any definable pathology, such as urinary infection, carcinoma, or cystitis induced by radiation or medication. A diagnosis of IC is often reached as a diagnosis of exclusion, where patients have tried treatments for other diseases exhibiting similar symptoms and those treatments have failed to alleviate the symptoms. The disease is best understood as a continuum, with an early phase in which symptoms are intermittent, a middle phase in which symptoms may be chronic and flare episodically, and sometimes a late phase in which bladder destruction occurs. In its early stages, IC is often mistaken for other urologic or gynecologic disorders, and tends to go unrecognized until its advanced stages. Treatment options for IC are limited. There are few oral or intravesical medications that have shown efficacy in treating IC. Physical intervention in the form of a cystectomy is used as a last resort in end stage disease. Although IC was traditionally diagnosed almost exclusively in women, the number of men diagnosed with IC has been increasing as well.
Although oral medications, such as pentosanpolysulfate (Elmiron®) and hyaluronic acid, are used to treat IC by replacing missing components in a defective glycosaminoglycan (GAG) barrier, a fundamental characteristic of IC, the use of oral anesthetic agents to inhibit urinary tract sensory nerve activation is impractical. Oral drug delivery affects the entire body, requiring high oral doses of drugs to achieve therapeutically significant levels in a target organ. When the organ is in the urinary tract, such as the bladder or urethra, oral drugs must pass through and be affected by other organs before reaching their target. This effect may change the activity or function of the drug resulting in undesirable side effects or other co-morbidities. An alternative to oral delivery is topical or site-specific delivery of the drug, where the drug is delivered directly to the diseased organ. Topical drug delivery generally provides similar efficacy at lower drug doses than oral delivery, and may reduce or eliminate the effect of the drug on any other organs than the target organ.
The use of urethral suppositories for topical drug delivery has been known. However, existing modalities do not allow for an efficient absorption of some beneficial therapeutic agents. What have been needed are systems and methods for efficient delivery of therapeutic agents to at least a portion of the tissue of a patient's urinary tract, or surrounding tissue thereof.